Dr Paul Henderson (Kent Taylor) is taking his wife Carla (Beverly Powers) to the so-called Blood Island where he plans to investigate the local flora and fauna, having heard that the atomic bomb tests the region suffered has had a strange effect on them. Along for support is his Peace Corps assistant Jim Farrell (John Ashley), but it's his wife he should be worried about: she doesn't throw herself at Jim, but on the boat trip she allows herself to be seduced by one of the crew. However, there will be more than adultery for the doctor to be bothered by - something very dangerous is happening on the island.
This was the first of the Blood Island series that Filipino director Eddie Romero brought to the world, often with the help of imported American star Ashley who had fallen in love with the place - the Philippines, that was, not Blood Island. These movies were distributed around the world, and often seen in drive-ins for those countries which had them, but nowadays they have been relegated to the appeal of camp, tolerated for their excesses and the amount of cheap laughs you can garner from them. They were all pretty silly, but had a certain dedication to their lurid dramatics which won them a following.
Not that Brides of Blood was enjoyable on any other level than how ridiculous it got as you couldn't imagine many finding it especially scary, not with the proliferation of rubber monsters. Once our hardy trio land on the island, they are alarmed to see the last part of a native ritual which involves dumping body parts in the sea, and Carla lets out a scream because it's that kind of film (this was one of the last films where Powers was known by her stage name, Beverly Hills; she retired from the screen some time later to perform good works as a minister on Hawaii). They proceed to the village, where it seems they harbour a guilty secret.
That being they regularly sacrifice their womenfolk to a rampaging monster, which given that it's a fairly small village, might have you considering that it's surprising there's anyone left there at all - these rituals seem to occur every night, so unless the birth rate had become abnormally high due to the radiation before long you'd imagine the tribe would consist solely of dejected menfolk. Anyway, Jim is understandably horrified by this turn of events and means to put a stop to it, but then the whole island appears to be hostile, including the plants and trees which extend roots and branches to grab passersby for prime "Argh! It's got me!" acting from the cast.
Not only that but the animals have been affected too - not very big animals, it has to be said, with one major setpiece involving Dr Henderson battling and being nipped by a rampant butterfly, which is as exciting as that sounds. But what of the monster? What can they do about that, a pressing matter for Jim as the next potential sacrifice is Alma (Eva Darren) who he has fallen for? It so happens there's a millionaire philanthropist there too, in the shape of Esteban (Mario Montenegro), and although he forcibly employs a tribe of pygmies as manservants he seems a nice enough chap. Can he assist in stopping the killings, or (strokes chin contemplatively) could it be that he has some, more personal connection to what is going on? Needless to say you'll be racing ahead of the characters as far as solving that mystery goes, but it does offer mild amusement for those who like their horrors cheesy and silly; everyone else may find it a test of the patience.